The　effect　of　nutrient　(N　and　P)　deficiency　on　activated　sludge　settleability　and　characteristics　of　activated　sludge　floes　in　Sequencing　Batch　Reactor　(SBR)　fed　with　brewery　wastewater　were　investigated.　The　results　showed　that　the　activated　sludge　had　good　settling　properties　at　influent　BOD　5/N/P　was　100/5/1,　100/5/0.8　and　100/4/0.8　respectively.　When　BOD5/N/P　was　100/0.94/0.31,　100/2/0.4,　100/3/0.6　respectively,　the　sludge　settleability　became　worse　due　to　excessive　growth　of　filamentous.　When　BOD5/N/P　was　100/0.94/1,　100/5/0.31,　100/5/0.4,　100/5/0.6　respectively,　non-filamentous　activated　sludge　bulking　occurred.　Adding　sufficient　nutrient　to　the　influent,　the　sludge　bulking　was　controlled　effectively　and　the　low　SVI　was　recovered.　When　increasing　COD　loading　rate,　the　duration　of　recovery　could　be　diminished.　When　nitrogen　and　phosphorus　were　insufficient　synchronously,　aerobic　granular　sludge　was　formed　which　was　averagely　2mm∼6mm　in　diameter.